Valve



ff 'f csozz/ J. GQ woQD ETAL VALVE Original Filed VTune 24, 194B Feb. 3, 1953I Patented Feb. 3, 1953 VALVE John G. Wood, Birmingham, and Andrew V. Jackson, Detroit, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Original application June 24, 1942, Serial No. 448,236. Divided and this application August 30, 1947, Serial No. 771,416

'The exhaust valves of internal combustion engines are in need of esp-:cial attention now that high octane fuels and high compression ratios are being used. At present the approved and accepted practice is to maize such valves of chrome nickel alloy steel. Apparently the chromium of the alloy serves-to render the valves resistant to the corrosive effects of the exhaust gases. Applicants believe that the chromium whichV isruseful is largely that lying adjacent the surface and `that the chromium remote from the surface has little value in resisting corrosion. They therefore propose to limit the use of chromium to a surface coating and to that end propose a coating of chromium by electrolysis. This will have the advantage of eliminating the greater weight present in a valve made from chrome nickel steel. It will also reduce the cost.

rllhis application is a division of applicants copending application Serial Number 448,236, filed June 24, 1942, now abandoned.

The question arises as to the foundation upon which the chromium shall be plated. In a companion application it has been proposed to plate chromium upon a core fabricated to Valve form from low carbon steel. In the present case it is proposed to use a core of a suitable metal having a relatively low melting point. Lead is one such metal. Upon this core is plated a shell of copper, brass or similar material to provide the necessary strength and upon the brass shell is plated a layer o1"- chromium. After plating with copper it is proposed to melt and remove the core. In this way there is made a very light valve which will not require a heavy Valve spring. The surface coating will render it resistant to the corrosive eects of the exhaust gases. The cavity resulting from the removal of the core may be supplied with any desired cooling medium, such as sodium or mercury or others heretofore used. Such a valve should make possible the use on ordinary motor vehicles of engines having high compression ratios and operated by high octane fuels without resort to the heavy chrome nickel valves which are expensive to fabricate and machine and which lack good heat conductivity.

Such a valve is illustrated on the drawing where Figure 1 shows a core of lead or some metal having a low melting point. Figure 2 shows, in section, the copper or brass plating over the lead core. Figure 3, also in section, shows the chromium plating over the copper, the lead core having been removed. Figure 4 shows, in elevation and partly broken away and in section, the cornpleted valve with a cooling medium within the cavity formed by removal of the lead.

8 Claims. (Cl. 12S-188) Referring tothe drawing the numeral 5 represents a core of lead or of some metal having a melting temperature which is low relative tothe metal shell which is to surround it. It is fabri# cated to the shape desired by extrusion or by any preferred method. A tappet abutment or plug l, preferably formed of alloy steel and `apertured as at 9, is positioned at the end of the stem portion of the core and the two parts, the core and plug, are electroplated with copper or brass, the shell of copper so formed being marked Il and serving to hold the plug because of its interlocked engagement with the recessed part I3 of the latter. The assembly of lead core, the plug and the shell is shown in Figure 2. The shell is of suiiicient structural strength for the purpose which it is to serve. The article so formed may then be heated sufficiently to melt the lead or other core which, as stated, has a melting point lower than that of the shell. The molten core may be removed through the plug aperture 9. Upon the shell Il is now plated a coating of chromium or some metal well adapted to resist the corrosive effects of the gases which are exhausted from the cylinders of internal combustion engines. This surface coating is marked l5.

Into the cavity of the valve so formed and through aperture 9 there may be supplied any preferred cooling medium, such as sodium, which will be in liquid form at a rather low temperature. This is shown at il. The aperture is then closed by a plug I9. Such a valve will be light and cornparatively inexpensive. lt will resist the corrosive effects of the exhaust gas due to the chromium plating and the heating eiect of the exhaust gas due to the high heat conductivity of the copper, and thus it will make possible the use of engines having high compression. ratios and using high octane fuel without the expensive alloy valves now being used for such engines.

For some purposes, as where a sodium or salt coolant is not needed, the core need not bemelted out and may remain as a constituent part of the valve.

We claim: 1. An internal combustion engine poppet valve consisting of a thin shell of copper and a coating of chromium thereon.

3 a steel tappet abutment mechanically interlocked with the end of said stem of said shell and said shell being coated with chromium.

4. A valve for high temperature fluids, the body of said valve consisting of a thin shell of copper having a uniform thickness, said shell constituting the essential structural portion of the valve, a coating of chromium on said shell, said coating of chromium protecting said copper shell from corrosion.

5. An internal combustion engine poppet valve, said valve consisting of a shell formed to provide the stem and head ofv the valve and being the essential structural supporting element of said valve, said shell being formed of thin copper of uniform thickness to evenly transmit and distribute the heat through the shell, and a chromium coating on said shell to prevent corrosion.

6. An internal combustion engine poppet valve consisting of a thin shell of a copper 'base alloy Vand a coating of chromium thereon.

7. An internal combustion engine poppet valve, the stem and head formed of a thin shell of copper base alloy, a tappet abutment mechanically interlocked with said shell at the stem end thereof and a coating of chromium on said shell.

8. In an internal combustion engine, a poppet valve consisting of a stem and head of a thin hollow shell of a copper base alloy, forming a hollow Valve, a steel tappet abutment mechanically interlocked with the end of said stem of said shell and said shell being coated with chromium.

JOHN G. WOOD. ANDREW V. JACKSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain July 27, 1944 

1. AN INTERNAL COMBUSTION ENGINE POPPET VALVE CONSISTING OF A THIN SHELL OF COPPER AND A COATING OF CHROMIUM THEREON. 